Wellbores are formed in subterranean formations for various purposes including, for example, extraction of oil and gas from the subterranean formations and extraction of geothermal heat from the subterranean formations. A wellbore may be formed in a subterranean formation using a drilling assembly including a drill bit coupled, either directly or indirectly, to a distal end of a drill string that includes a series of elongated tubular segments connected end-to-end and extending into the wellbore from the surface of the subterranean formation.
The drill bit can be any conventional earth-boring rotary drill bit, such as a fixed-cutter drill bit (also known in the art as a “drag” bit), a roller cone drill bit (also known in the art as a “rock” bit), a diamond-impregnated bit, or a hybrid bit (which may include, for example, both fixed-cutters and roller cone cutters). For example, the drill bit can be a fixed-cutter drill bit, which typically includes a plurality of wings or blades each carrying multiple cutting elements configured and positioned to cut, crush, shear, and/or abrade away material of the subterranean formation as the drill bit is rotated under an applied axially force (known in the art as “weight-on-bit”) to form a pilot borehole therein.
The drill string can include a variety of components (e.g., tools), such as one or more of an expandable reamer, an expandable stabilizer, and a fixed stabilizer. The expandable reamer can include expandable reamer blades configured for enlarging the pilot borehole formed by the drill bit to form an expanded borehole in the subterranean formation. The expandable stabilizer is typically provided above (i.e., “up-hole” of) the expandable reamer, and can include expandable stabilizer blades configured to extend to a diameter of the expanded borehole to increase the stability of the drilling assembly during the operation thereof. In turn, the fixed stabilizer is typically provided below (i.e., “down-hole” of) the expandable reamer, and can include fixed stabilizer blades configured to extend to a diameter of the pilot borehole to increase the stability of the drilling assembly during the operation thereof. The fixed stabilizer can also be provided at other locations along the drill string. The drill string can, optionally, be run through the pilot borehole in the subterranean formation without the drill bit coupled thereto.
Disadvantageously, the radially outermost surfaces and edges of one or more components of a conventional drilling assembly can contribute to vibrational instabilities during the operation of the drilling assembly. For example, gauge regions (i.e., regions which define the outermost radii of particular components of the drilling assembly) of the blades of one or more components (e.g., the drill bit, the expandable reamer, the expandable stabilizer, and the fixed stabilizer) of the drilling assembly can be configured with relatively sharp and aggressive rotationally leading edge engagement profiles that can cause the gauge region of the blade to undesirably dig into or catch the inside of a borehole (e.g., the pilot borehole, or the expanded borehole) sidewall, inducing whirl and stick slip vibrations during operation of the drilling assembly.
Accordingly, it would be desirable to have drilling assembly components, drilling assemblies, and methods of stabilizing drilling assemblies, facilitating enhanced stability during operations to form a wellbore in a subterranean formation as compared to conventional drilling assembly components, drilling assemblies, and methods of stabilizing drilling assemblies. It would be further desirable, if the formation-engaging surfaces and edges of the gauge regions of the drilling assembly components were sufficiently wear-resistant to form the wellbore in the subterranean formation without undergoing excessive wear (e.g., abrasive wear, erosive wear) so as to prolong the operational life of the drilling assembly components and the drilling assembly.